This was sort of by design based on other opinions. Some of the applications in DNSSEC-Tools are optional and thus by not requiring everything be installed you save the installation footprint a bit if you didn't need, say, mapper.
That being said I've always thought that line of thinking was pseudo-silly on a system with pre-built packages. So I'll add GraphViz back to the requires list and point at this bug if someone complains :-)

Package dnssec-tools-1.14-7.fc18:
* should fix your issue,
* was pushed to the Fedora 18 testing repository,
* should be available at your local mirror within two days.
Update it with:
# su -c 'yum update --enablerepo=updates-testing dnssec-tools-1.14-7.fc18'
as soon as you are able to.
Please go to the following url:
https://admin.fedoraproject.org/updates/FEDORA-2013-11484/dnssec-tools-1.14-7.fc18
then log in and leave karma (feedback).

I could, but I think I'll try it like this now. There are some systems where GraphViz and some other tools aren't available (RHEL systems don't have everything needed), so I didn't include requirement for those systems.